LOCATION TEFTON CO+NM
Established Series
Rev. JPP/TWH/KLS
03/2018
TEFTON SERIES
The Tefton series consists of very deep, somewhat poorly drained soils that formed in alluvium derived from sedimentary and igneous rocks. Tefton soils are on flood plains, flood plain steps and valley floors and have slopes of 0 to 3 percent. Mean annual precipitation is about 457 mm and mean annual air temperature is about 8.3 degrees C.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Oxyaquic Haplustepts
TYPICAL PEDON: Tefton loam, pastureland. (Colors are for dry soil unless otherwise stated.)
A--0 to 13 cm; light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many fine roots; slightly effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (8 to 30 cm thick)
Bw--13 to 43 cm, pale brown (10YR 6/3) loam stratified with very fine sandy loam, brown (10YR 4/3) moist; weak coarse subangular blocky structure parting to moderate fine granular; soft, very friable; nonsticky and nonplastic; many fine roots; slightly effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (20 to 38 cm thick)
C1--43 to 142 cm, pinkish gray (7.5YR 6/2) loam stratified with fine sandy loam and very fine sandy loam, brown (7.5YR 4/2) moist; massive; soft, very friable, nonsticky and nonplastic; many fine roots; slightly effervescent; common prominent masses of yellowish brown (10YR 5/6) moist, iron concentrations; moderately alkaline (pH 8.0); clear smooth boundary. (51 to 114 cm thick)
2C2--142 to 178 cm; stratified very gravelly sand and gravelly loamy sand; 45 percent gravel; 2 percent cobble; neutral.
TYPE LOCATION: La Plata County, Colorado. About 5 km south of Hermosa, about 823 meters east and 183 meters south of the northwest corner, Section 15, T. 36 N., R. 9 W. U.S.G.S. Hermosa quad.; Lat. 37 degrees, 23 minutes, 02 seconds N., and Long. 107 degrees, 50 minutes, 29 seconds W., NAD 27.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 8.3 to 10.0 degrees C.
Mean summer soil temperature: 15.6 to 18.9 degrees C.
Depth to the contrasting 2C2 horizon: 100 to 152 cm
Depth to saturation: 61 to 91 cm in spring and summer
Particle-size control section (weighted averages):
Clay content: 18 to 25 percent
Rock fragments: 0 to 3 percent
A horizon
Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 3 to 5 moist
Chroma: 2 or 3, dry or moist.
If the value is as low as 5 dry and 3 moist, the thickness of the layer is less than 7 inches.
Texture: loam, very fine sandy loam
Clay content: 10 to 27 percent
Rock fragment content: 0 to 3 percent gravel
Calcium carbonate equivalent: 1 to 5 percent
Reaction (pH): 7.4 to 8.4
Bw horizon
Hue: 7.5YR or 10YR
Value: 5 or 6 dry, 4 or 5 moist
Chroma: 2 to 4 dry or moist
Texture: loam, fine sandy loam
Clay content: 15 to 27 percent
Rock fragment content: 0 to 5 percent gravel
Calcium carbonate equivalent: 1 to 5 percent
Reaction (pH): 7.4 to 8.4
C1 horizon
Hue: 5YR to 10YR
Value: 5 or 6, 3 to 5 moist
Chroma: 2 to 4 dry or moist.
Texture: stratified loam, clay loam, fine sandy loam or very fine sandy loam
Clay content: 15 to 30 percent
Rock fragment content: 1 to 5 percent
Calcium carbonate equivalent: 0 to 5 percent
Reaction (pH): 7.4 to 8.4
2C2 horizon
Texture: Stratified very gravelly sand and gravelly loamy sand, stratified extremely gravelly loamy sand and extremely gravelly sand, extremely gravelly loamy sand, very gravelly sand, gravelly loamy sand
Clay content: 0 to 5 percent
Rock fragment content: 30 to 70 percent gravel, 0 to 15 percent cobbles
Reaction (pH): 7.4 to 8.4
COMPETING SERIES:
Steimer (CO) - have a mean annual soil temperature more than 10.0 degrees C.
GEOGRAPHIC SETTING:
Landform - flood plains, flood plain steps, valley floors
Elevation - 1,830 to 2,290 meters
Slope - 0 to 3 percent
Parent material - alluvium derived from sedimentary and igneous rocks
Mean annual air temperature - 7.2 to 11.7 degrees C.
Mean summer air temperature - 15.0 to 18.3 degrees C.
Mean annual precipitation - 400 to 510 mm
Precipitation pattern - distributed fairly even throughout the year with May and June being the driest months and July and August being the wettest months. PE Index is about 50 at the type location.
Frost-free period - 100 to 130 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; low runoff; moderate or moderately slow permeability. These soils are subject to rare flooding.
USE AND VEGETATION: This soil is used for irrigated crops, irrigated pasture and range. Native vegetation is mainly tufted hair grass, slender wheatgrass, western wheatgrass, sedges, rushes, cottonwood trees, and willows.
DISTRIBUTION AND EXTENT: Western Colorado and northern New Mexico; LRR D, E; MLRA 36, 48A; small extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: La Plata County Area, 1982. The name is from a railroad siding.
REMARKS:
Diagnostic horizons and features recognized in this pedon are:
Cambic horizon: 13 to 43 cm (Bw horizon)
Lithologic discontinuity: 100 to 152 cm (2C2 horizon)
Endosaturation: 43 to 142 cm (C1 horizon)
Redoximorphic concentrations: 43 to 142 cm (C1 horizon)
Particle-size control section: 25 to 100 cm (part of the Bw and part of the C1 horizons)
Stratification occurs in the Bw and C1 horizons
The chroma of 2 in the C1 horizon is from the parent material, not from aquic conditions.
Tefton soils have a mesic soil temperature regime and are in an ustic soil moisture regime with an oxyaquic subclass.
The 4/2004 revision changes the classification from Aquic Ustifluvents to Oxyaquic Haplustepts based on recognizing the Bw horizon (formerly AC) as a cambic, and recognizing that the soil lacks iron depletions for an aquic subgroup.
National Cooperative Soil Survey
U.S.A.